Had this problem at one of the ACs. They love nesting in the gaps between the compressor and the walls. Did everything including putting spikes, pour boiling water during nights, or picking up the eggs but that only stopped the current couples and still new couples will replace them sooner than you thought.

So all I did is to hang the compressor by 40cm to expose the floor and ever since then they stopped nesting.

The only part that you need to beware of is they may try to enter the compressor (which is impossible to nest in but their feathers may be stuck to the fin) or nest around the steel bracket that carries the compressor, but that is much more manageable as you can either push of the nest to plummer down or you can choose to pick up the eggs for a nice snack or destroy the in front of this flying vermins.